Power BI Report Server- Loading report in Web page gives undefined error with status code 500

 Dhivya_123456 
Yes, Even when your report is set to Import mode, you still need to provide the proper data source permissions in the Power BI service or Report Server.

Here’s why from my experience:

When you refresh a report in Power BI Desktop and publish it, you’re essentially uploading a snapshot of the data at that moment. But once it’s published, the Power BI service or Report Server runs its own scheduled or on-demand refreshes to keep the data up to date. Those refreshes require access to the original data source, so the service or gateway uses the configured data source credentials to connect and pull fresh data.

So, even though the data is imported (cached inside the PBIX), the service still needs permission to reach the data source during refresh operations. If the credentials or permissions aren’t set properly in the service or gateway, you’ll run into connectivity or permission errors after a while ,which explains why the error comes back even after republishing.

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Hi Dhivya_123456 ,

Thanks a lot grazitti_sapna  for the detailed explanation your clarification on Import mode and why PBIRS still needs data source permissions is spot on. That’s definitely one of the key reasons why the error keeps coming back after republishing.

Just to add (for anyone else facing the same issue), a couple of additional points that usually help this down.

1. Check the Data Source Credentials in Report Manager

* Go to the report in the PBIRS web portal → click the dropdown → Manage → Data Sources.

* Make sure the credentials are stored securely and test the connection.

* Even for Import datasets, the server still validates the source at refresh time.

2. Clear Cache & Temp Files

* Sometimes the ReportServer TempDB or the RS cache folders hold onto stale metadata, which can surface as 500 errors. Restarting the PBIRS service and clearing temp files often resolves intermittent crashes.

3. Server Logs

* Check the RSPortal and RSService logs under:

C:\Program Files\Microsoft Power BI Report Server\PBIRS\LogFiles

*These logs usually give the exact failing data source or permissions issue behind the generic “undefined” error.

4. Upgrade if Possible

* If you’re not on the latest PBIRS build, consider upgrading. Several “500 undefined” bugs were fixed in cumulative updates.

With the above your guidance on permissions, should have a complete, if you still face any issue we are happy to help you.

Thanks,
Akhil.